Improvement in furnaces for zinc-white



S.v WETHERILL.y

MakingV White Zini-c.

Patented Sem.` 30. 1856.

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' UNiTEn Afri-SNT ENCE@ sAMUEL WETHEEILL, oEBErI-ILEHEM, rENNsYLvANiA.

IMPROVEMENT IN FURNACES FOR ZINC-WHITE.

Specification forming part of Letters Patent No. MLS, dated September30, 1856.

To all whom, it may con/cern:

Be it known that I, SAMUEL WETHERILL, of Bethlehem, in the State ofPennsylvania, have invented certain new and useful Improvements inFurnaces for the Production of the White Oxide of Zinc by the DirectAdmixture of the Ore with the Fuel, of which the following is a full,clear, and exact description, reference being had to the accompanyingdrawings, making part `of this specification, in which?` Figure lis aperspective view of the furnace 5 Fig. 2, a longitudinal verticalsection in the plane of the axis of the grate; Fig. 3, a verticalcross-section, and Fig. 4, a horizontal section taken above the grateand bed of the furnace.

The same letters indicate like. parts in all the figures.

In the process of manufacturing the'white oxide of zinc by the admixtureof the ore with the fuel invented by me, and for which I have heretoforemade application for the grant of Letters Patent, I discovered that forthe praetical working of that process it was necessary to have the bedof the furnace on which the charge of mixed ore and coal is putperforated with numerous small holes leading` to a blastchamber below,so as to subdivide the forced blast of atmospheric air, and thus producea multiplicity of blow-pipes, each concentrated upon a small proportionof the charge to effect the combustion of the coal at an intensitysufficient to decompose the ore and vaporize the metallic ingredient,and to furnish a supply of atmospheric air sufficient not only toproduce the required intensity ofcombustion, but to reoxidize the zincas it is given out in the form of vapor; and I also discovered that itwas necessary to the practical working of this process that theformation of slag to any considerable degree on the surface of theperforated bed should be prevented.

In view of the process to be worked andthe effects required to beproduced, my invention consists in making the whole or a part of the bedof the furnace so that it can be vibrated during theworking of thefurnace to prevent slag from forming and adhering lto the bed of thefurnace.

My said invention does not consist simply in making the whole or a partof the bed of a furnace so that it can be vibrated, as the grate for thefire-place of a stove or furnace made to vibrate for loosening theclinker has long been known, but my said invention consists in giving avibratory motion to the whole or part of the bed of a furnace used forthemanufacture of the white oxide of zinc by the direct admixture of theore and fuel placed ou a bed perforated with numerous small holes, andcombined with a forced blast, which passes to the mixed ore and fuel innumerous small forced jets to effect thecombustion of the fuel, thedecomposition of the ore,the vaporization of the zinc, and the oxidationof the vapor thus evolved. V

In the accompanying drawings@ represents the body of the furnace inwhich the process is to be Worked, and b the air-chamber below, in whicha forced blast of atmospheric air is to be introduced from some suitableblower through an aperture, c, in the front wall, and entering theair-chamber b through an aperture, d, in the side wall e, governed'loy asliding damper, f, operated by a rod, g, which projects in front. Thewalls hh from the foundation up to the liner' may be double, with anair-space, j, between them, and at the top of these walls, at the levelofthe line @'is placed a metal plate, It', which forms part of the bedof the furnace. Over the edges of this plate the side and end Walls arecarried to the required height to form the body of the furnace, which isarched over, as at Z, leaving an aperture, m, to carry off the products,as may be required. The metal plate or part of the bed k inclinesdownward for a short distance atan angle of about forty-five degreesfrom the side and-end walls, the lower edge of the sides being paralleland the ends presenting segments of circles to correspond with the uppersurface of a plate, n, which is placed under the inclined sides of theplate This plate n is inthe form of a segment of a cylinder extendingthe whole length of the inside of 'the furnace, and itsinner peripheryis secured to arms 0, projecting radially from a horizontal shaft, p,hung in suitable boxes in the end walls, one end of the shaft extendingthrough the front wall and there provided with a crankarm to receive aconnecting-rod from some suitable motor by which it can be vibratedduring the working of the furnace. The vibration should be verysmall-say about onequarter of an inch at the periphery of thecylindrical plate n.

In a suitable establishment for the manufacture of the white oxide ofzinc several furnaces can be erected in a line side by side, so that allthe crank-arms can be operated by one connecting-rod from thesteam-engine employed for working the blowers. When the cylindricalplate n is in place, its outer periphery will just work freely under theedges of the inclined parts of the plate 7c, and these togetherconstitute the bed of the furnace, and should be perforated all overwith holes of about one-quarter of an inch in diameter at the uppersurface and larger below, and about one inch apart from center tocenter. It is important to make the holes conical and smaller at topthan at bottom to prevent clogging.

In starting the furnace a thin layer of anthracite coal, of the sizeknown as chestnutcoal, is laid on the perforated bed andignited, andthen a layer of mixed coal and ore put on top to the depth of aboutthree inches.

The manner of preparing and working the charge is to be conducted asfully described in my application for a patent for the process ofmanufacturing the white oxide of zinc, and as is well known to themanufacturers of the white oxide of zinc, having been practiced eX-tensively at Bethlehem, Pennsylvania. During the working of the chargethe blast of atmospheric air must be continued, and the shaft vibratedlto keep the plate n, on which the main part of the charge rests, inmotion,

the effect of which will be -to prevent slag from forming and uniting onthe surface of tions clear for the free passage of the blast. In

this way the serious inconveniences arising from the accumulation ofslag and its adhesion to the perforated bed is avoided.

The perforated plates k and n, constituting the bed of the furnace, maybe made of series of perforated bars fitted side by'side; and although Ihave made them ofv metal, I do not wish to confine myself to metal, asother refractory substances may be substituted.

It will' be obvious that instead of making the Vibratory part of theperforated bed in the form of a segment of a cylinder it can be madeiiat and vibrated in a horizontal plane instead of a cylindrical plane;but I do not claim such form.

Vhat I claim as my invention, and desire to secure by Letters Patent,is-

Making the whole or a portion of the bed of the furnace to vibrate forthe purpose and in the manner substantially as described, but this Ionly claim when the bed is perforated with numerous small holes, andwhen used in combination with a forced blast of atmospheric air, whichpasses to the charge of mixed ore and fuel in numerous small forcedjets, substantially as and for the purpose specified.

SAML. VETI-IERILL.

Witnesses:

WM. W. MEREDITH, J. S. RAUcH.

